1. Field of the Invention
The present invention relates in general to an FDMA (Frequency Division Multiple Access) transmitter-receiver and more particularly to an FDMA transmission/reception method for use in a digital radio communication system which is capable of changing a communication channel bandwidth, and a transmitter-receiver employing the FDMA transmission/reception method.
2. Description of the Related Art
A digital radio communication system is generally designed in such a way that a plurality of local stations transmit/receive the respective radio waves to/from a base station and the communication is established between the local stations via the base station. Therefore, the base station needs to multiplex the signals on all the call channels or communication channels which are assigned to the communication system of interest in order to transmit/receive the resultant radio wave. As such multiplexing communication methods, there are known the Time Division Multiple Access (hereinafter, referred to as "a TDMA" for short, when applicable) method in which multiplexing is carried out in time domain and the Frequency Division Multiple Access (hereinafter, referred to as "an FDMA" for short, when applicable) method in which multiplexing is carried out in frequency domain.
On the other hand, the promotion of the multi-media in recent years results in the demand of carrying out communication between terminals having various data rates being developed. In order to cope with the promotion of the multi-media, it is desired that the rate of data which can be transmitted/received by the communication system can be changed.